1. Field of the Invention
The present invention relates to substances which inhibit both gram positive and gram negative bacteria food products. More specifically, these compositions include propionibacteria metabolites, lantibiotics, and phosphate salts which function as a chelating agent to bind the propionibacteria metabolites and lantibiotics to the surface of the substrate being treated.
2. Technology Description
There has been extensive research conducted in the field of food safety to develop compositions which function as antibacterials. However, most compositions tend to have enhanced effectiveness against either gram positive or gram negative bacteria and as a result, may not be truly effective against both types of bacteria. In addition, there exists a need in the art for improved ways of chemically delivering the antibacterial to the substrate to be treated to enhance efficacy. Relevant Prior art may be found in U.S. Pat. Nos. 5,096,718 and 5,260,061 and the references cited therein. These patents disclose the use of metabolites of propionic acid bacteria in certain foods to increase the shelf life of the resulting products. These metabolites demonstrate enhanced efficacy against gram negative bacteria but are not as effective against gram positive bacteria.
JP 07-115950 suggests the combination of bacteriocins produced by lactic acid bacteria of propionibacterium in combination with either organic acids and their salts, fatty acid esters of polyhydric alcohols, amino acids, antibacterial peptides and proteins, polysaccharides comprising sugars, saccharic acids and amino sugars and their partial decomposition products, spices and their essential oils and plant components; and alcohols. The reference fails to suggest that the combination can be used to prevent the deterioration of foods as a result of mold and yeast (i.e., provide an antimycotic effect) by using the combination of bacteriocins with organic acids and their salts, fatty acid esters of polyhydric alcohols, amino acids, antibacterial peptides and proteins, polysaccharides comprising sugars, saccharic acids and amino sugars and their partial decomposition products, spices and their essential oils and plant components; and alcohols.
U.S. Pat. No. 5,217,250 suggests the use of nisin compositions as bactericides. Nisin is a lantibiotic, more specifically, a polypeptide with antimicrobial properties which is produced in nature by various strains of the bacterium Streptococcus lactis. Nisin is primarily effective against gram positive bacteria. This patent suggests that the combination of a chelating agent, such as EDTA or other acetate salts or citrate salts with nisin can result in a broad range bactericide.
U.S. Pat. Nos. 5,573,797; 5,593,800 and 5,573,801 disclose antibacterial compositions which include a combination of a Streptococcus or Pediococcus derived bacteriocin or synthetic equivalent antibacterial agent in combination with a chelating agent. The composition is applied to the surface of the food to be treated either by direct application or by incorporating the composition onto a flexible film casing which is placed into intimate contact with the food surface.
U.S. Pat. No. 5,458,876 suggests the combination of a lantibiotic with lysozyme as an antibacterial.
EP 0 466 244 discloses a composition having improved antibacterial properties comprises a mixture of at least one of each of the following groups of compounds: (I) a cell wall lysing substance or a salt thereof, (II) an antibacterial compound and (III) an adjuvant selected from organic acids acceptable for use in food products or preparations for cosmetic use or personal hygiene or salts of these acids, phosphates and condensed phosphates or the corresponding acids, and other sequestering agents. Preferably (I) is lysozyme, (II) may be a bacteriocin (e.g. nisin or pediocin), and (III) may be acetic acid, lactic acid, citric acid, propionic acid, tartaric acid, orthophosphates, hexametaphosphates, tripolyphosphates, other polyphosphates or sequestering agents containing substituted or non-substituted amino groups, e.g. EDTA.
EP 0 453 860 suggests the combination of nisin with a phosphate buffer effective at a pH of between 5.5. and 6.5 to eradicate gram negative bacteria from surfaces.
Despite the above teachings, there still exists a need in the art for a composition which is effective against a broad range of bacteria, specifically one which demonstrates efficacy against both gram positive and gram negative bacteria, and one which will readily attach to a substrate so that even higher levels of microbial control can be attained.